cases observed and a wide experience with this disease both 

 in Cuba and the United States no case has been found where 

 the source of infection could be traced directly to wound 

 infection, except in those cases that were experimentally 

 inoculated. In the central United States it is a common 

 practice to cástrate the males and dehorn all calves. If blackleg 

 is produced by wound infection cases would frequently follow 

 such operations, but such is not the case, in fact these surgical 

 operationes seem to check the spread of blackleg and are 

 frequently resorted to by cattlemen as a means of suppression 

 when the disease occurs in their herds. It is possible that the 

 haemorrhage that follows these operations may prevent its 

 progress a little. 



It is possible, if not probable that infection may take 

 place either by inhaling the germs or taking them with the 

 food although experiments made in Kansas by drenching 

 susceptible calves with virulent material failed to transmit 

 the disease. As blackleg occurs in young animáis it is possible 

 that infection may take place through wounds that result 

 from shedding the temporary, or cutting the permanent 

 teeth. At present we can only say that the common mode of 

 blackleg infection is not definitely known. 



PERIOD QF INCUBATION. 



The period of incubation is the time that elapses after 

 the germs are taken into the body of the animal, and before 

 symptoms of the disease appear. This varíes according to 

 circumstances from six hours to four or five days. 



SYMPTOMS. 



The symptoms vary with the part of the body attacked. 

 Blackleg generally attacks the muscles of one shoulder or 

 quarter, some times the muscles of the back or neck and in 

 a few cases the muscles of the whole body may be affected. 

 The first symptom usually noticed is that the calf is lyiug 

 down apart from the others and not ruminating ("chewing 

 the cud"). If the calf is made tomoveitdoes so with difficulty; 



